Sealed, waterproof digital electronic camera system and method of fabricating same

ABSTRACT

A hermetically sealed digital electronic camera that is designed to operate both on land and underwater to great depths, and method of making same. The present invention is a camera which is hermetically sealed by being totally encapsulated, preferably by being cast in plastic, with no seals, holes, joints, penetrating pins, wires or other objects. Wireless means are used for communicating information, electrical power and control signals. The invention is impervious to atmospheric contamination and absolutely incapable of leaking under water to great depths and pressures. In an alternate embodiment camera optics are not encapsulated but are immersed in water when the encapsulated digital camera is placed in water.

RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 13/710,430, filed on Dec. 10, 2012, now U.S. Pat. No. 8,711,278issued Apr. 29, 2014, for a SEALED, WATERPROOF DIGITAL ELECTRONIC CAMERASYSTEM AND METHOD OF FABRICATING SAME, which is a continuation of U.S.patent application Ser. No. 13/037,805, filed on Mar. 1, 2011, now U.S.Pat. No. 8,330,854 issued Dec. 11, 2012, for a SEALED, WATERPROOFDIGITAL ELECTRONIC CAMERA SYSTEM AND METHOD OF FABRICATING SAME; whichis a Continuation of U.S. patent application Ser. No. 11/332,012, filedon Jan. 13, 2006, now U.S. Pat. No. 7,920,163 issued Apr. 5, 2011, for aSEALED, WATERPROOF DIGITAL ELECTRONIC CAMERA SYSTEM AND METHOD OFFABRICATING SAME; which is a continuation-in-part of U.S. patentapplication Ser. No. 09/808,912, filed on Mar. 14, 2001, now U.S. Pat.No. 6,987,527 B1 issued Jan. 17, 2006, for a SEALED, WATERPROOF DIGITALELECTRONIC CAMERA SYSTEM AND METHOD OF FABRICATING AND COMMUNICATINGWITH SAME; which is a continuation-in-part of U.S. patent applicationSer. No. 09/333,825, filed on Jun. 15, 1999, now U.S. Pat. No. 6,795,110B1 issued Sep. 21, 2004, for a WEATHERPROOF AND WATERTIGHT DIGITALELECTRONIC CAMERA, INCLUDING A SOLID OR FLUID-FILLED DIGITAL CAMERAOPERATING AT GREAT DEPTHS, by the same inventor, all of the disclosuresof which are incorporated herein by reference in their respectiveentireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally concerns digital electronic cameras, andwaterproof housings for cameras including digital electronic cameras.

The present invention particularly concerns (i) digital electroniccameras encapsulated in plastic, with no seals or penetrating pins,wires or other objects whatsoever, (ii) digital electronic cameras soencapsulated with no air or other gas whatsoever inside, (iii) digitalelectronic cameras with water-immersed adjustable optics, and (iv) thecommunication of information, electrical power and control across awatertight barrier particularly as may encapsulate and protect a digitalelectronic camera.

2. Description of the Prior Art

2.1 Relevant Previous Patents

A significant body of prior art concerning waterproof housings forconventional film cameras is substantially irrelevant to the presentinvention for several reasons. First, the housing or case for aconventional, non-electronic, camera must open for retrieval andreplacement of the film—as will prove to be unnecessary with a digitalelectronic camera. Second, since the camera's case or housing will open,and required replacement of batteries is readily accomplished byphysical substitution, no battery recharging need transpire through thecase or housing.

The case and its waterproof seals can be, and often are, quitesophisticated in supporting the transmission of mechanical forces andadjustments as may attend, inter alia, adjustment of the camera's focusand/or the actuation of its shutter. However, and although a digitalelectronic camera may have a focus adjustment and will have a shutter,these mechanisms can be electrically, as opposed to mechanically,actuated.

Accordingly, the present invention will prove more analogous to certainprior art underwater electronic devices—including electronic imagingdevices such as, inter alia, a video tape recorder—than to underwaterfilm cameras. (Of course, even with a video tape recorder, a watertightenclosure will open for access to the videotape.)

In this regard, U.S. Pat. No. 3,952,190 to Perkins for an UNDERWATERSTROBE FLASH UNIT concerns a method of waterproofing a strobe flash unitfor use in underwater photography. A mold is formed and a strobe flashunit is mounted within the mold. Epoxy resin is poured into the mold tosurround the strobe flash unit with the resin. The resin is then cureduntil it hardens, at which time the mold is removed from the epoxy resinand strobe flash unit. The resultant product is a strobe flash unitencapsulated in a transparent waterproof casing. Such encapsulation willbe seen to be suitably employed in the present invention.

As regards the communication of power to handheld underwater electronicimaging devices, U.S. Pat. No. 4,009,419 to Ligman for a SAFETY CIRCUITFOR VIDEO DIVER concerns an underwater diver who is provided with avideo camera, light, and communications all of which is supplied withelectrical current from the surface by a shipboard electrical circuit.The diver is protected from accidental excessive voltages and current bymagnetically isolating the diver's current from the shipboard currentand by employing optical feedback to control the voltages for the diver.Additionally, a standby battery is employed to energize this equipmentwhen the shipboard power fails. The entire shipboard power supply iscontained in a waterproof box upon which is also mounted a video monitorand a video recorder, both secured in watertight fashion to the box. Thepresent invention will be seen to involve the transmission of power intoa waterproof enclosure, but not while the enclosure is immersed, andnormally not while an electronic digital camera within the enclosure isin use.

The present invention will be seen to involve optical data transmission.U.S. Pat. No. 5,847,753 to Gabello, et al., for a CAMERA SYSTEM FORSCANNING A MOVING SURFACE concerns a camera system utilizing a line scan(linear array) camera designed to scan a moving surface and subsequentlyto generate and to transmit a high quality digitized video signal over along a distance by an optical fiber. The primary function of the systemis: to scan a moving surface using a 2048 or a 1024 linear array; tocondition and digitize the array analog video signal; and subsequentlyto transmit to a computer processing unit, without a noticeable loss infidelity, the digitized video data over a long distance by means of anoptical fiber connected to the camera and the computer processing unit.The system also functions to transmit both video signals and non-videoinformation signals over a fiber optic link from the camera to thecomputer processing unit.

2.2 An Exemplary Modification of an Existing Digital Camera

The present invention will be seen to employ but very, veryslight—substantially inconsequential—physical and electricalmodifications to an existing digital electronic camera. No modificationsat all are required by the present invention in the personal computer,nor in the operating software, that are commonly used to recover digitalimages from the digital electronic camera. However, all these things arereadily susceptible of modification, if required.

It is thus useful to consider the susceptibility of a digital electroniccamera to electrical and/or physical modification. An example ofmodifications—much more extensive than are required by the presentinvention—to an existing digital camera to support of its use in anon-standard, space borne, environment is shown in a Stanford Universitystudent project reported on the World Wide Web at<http://maverick.stanford.edu/.about.ssdl . . . System/payload/camera>.

2.2.1 An Exemplary Existing Digital Electronic Camera

The Logitech Fotoman Plus digital electronic camera is a 8-bit grayscaledigital camera, capable of storing 32 JPEG compressed pictures inmemory. Its specifications, according to Logitech, are as follows:

The camera dimensions are 16.8 centimeters (6.7 inches) by 8.1 cm (3.2in) by 3 cm (1.2 in). The camera weight is 284 grams (10 ounces).

Camera image quality is 256 gray levels over 496.times.360 pixels, foran equivalent resolution of 120 dots per inch (120 dpi) over a photoapproximately 4 in (12.7 cm) wide.times.3 in (8.9 cm) high.

The lens is fixed focus with a 8.5 millimeters (mm) focal length, f/4.5.The 35 mm camera equivalent focal length is 64 mm. Shooting range is 3feet (1 meter) to infinity.

The camera's equivalent film sensitivity is approximately ASA 200without the neutral density filter, and approximately ASA 25 with thefilter.

The camera's electronic shutter speed is 40 milliseconds (.about. 1/30)with the flash, and 0.5 to 50 msec ( 1/2000 to 1/20) without the flash.

The flash guide number equivalent is 27 at ASA 200. The flash shootingrange 3 ft (1 m) to 8 ft (2.5 m). The life of the flash is 10,000flashes.

The image capacity of camera is 32 pictures in an image storage medium:namely, solid state (dram) memory with battery backup.

The image sensor type is a CCD (charge-coupled device). The raw imagesize is 179 kb (8 bits per pixel). Compressed image size varies with theimage. Average compressed image size is 23 kb with 8:1 compression usingthe JPEG image compression method.

The adapter rings have a small end of 27 mm threaded outer diameter, anda large end of 37 mm threaded inner diameter.

The camera cable length is 6 ft. (2 m) of cable suitable for thecamera's RS423 serial interface (which is simply 5 v version of the moreuniversal RS232 serial interface, which will be seen to be the type usedin the preferred embodiment of the present invention).

The baud rate of the interface is 9.6 K baud receive, and 9.6K, 19.2K,38.4K, 57.6K, of 115 k baud transmit.

The main power source of the camera is two rechargeable nickel-cadmiumbatteries, AA size, 600 ma, 1.2 V. The time needed to charge theseNi-Cad batteries is 6 hours minimum. In estimating loss of charge in theNi-Cad batteries assume that, at room temperature, the batteries loseabout 20% of a full charge every time the camera takes one full load ofphotos (32 photos). The batteries lose about 15% of a full charge everytime the camera goes 24 hours without recharging.

The battery charger has an output 12 vdc v, −2 v, 500 mah minimum. Thepolarity-positive pole is at center.

A memory power source is based on a 3 v lithium cell.

Camera operating temperature and humidity is 0 to 40.degree. C. at 95%humidity or less. Camera storage temperature and humidity is −40 to50.degree. C. at 95% humidity or less.

An existing Logitech Fotoman Plus digital camera (the “Fotoman camera”)is modified by, among other things, placing it in a protective box. Thecapabilities of this digital camera include JPEG image compression,storage in DRAM of up to 32 496.times.360 images with 8-bit gray scalein compressed form. The compression results in a JPEG image size ofabout 23 Kb.

A serial link to the CPU, RS-232, is used to load into the Fotomancamera memory its operating software, to give it instructions, and totransfer back the camera status and full images.

The digital camera can be powered on/off, from the V bus of thespacecraft. A voltage regulator and a bypass capacitor are used toreplace the Ni-Cad batteries normally used to power the Fotoman Plus(see schematic) A lithium battery, used by the Fotoman to maintain theoperating software in memory, is left in the camera.

2.2.2 Exemplary Previous Electrical Modifications to an Existing DigitalElectronic Camera

In accordance with the present invention, connection will be made to thecircuitry of a digital electronic camera. That a connection to—and more,rising to the level of actual modification of—the circuitry of anexisting digital electronic camera might be made is known.

For example, the aforementioned Fotoman Plus digital electronic camerawas subjected to electronic modifications. The Fotoman Plus camera wasalready designed with appropriate digital communications interfaceswithout the need for any custom adapter. However, an external switchcontrolled by the on/off command from the CPU and voltage regulation hadto be added. It was so added by wiring an existing RS423 serialinterface from a bottom 6 electrodes already present in the camera.(With the lens on top, the six electrodes from left to right are: 1.Connection directly to the battery through a fuse, located in thecamera, which is used to monitor battery level in manufacturing. Abattery eliminator could be connected, but the fuse would have to bebypassed; 2. RS423 out; 3. Charge in (V); 4. RS423 in; 5. Ground, usedfor both power and RS423; and 6. Unused.)

Next, a power regulation and switching circuit were designed to turn onthe Fotoman camera if a “on” signal was received from the CPU throughthe bus of the space satellite in which the modified camera was to beflown, and contained.

Finally, the flash had to be selectively electronically disabled byremoving certain components off the PCB. (The components were C32, Q18,Q24, Q27, R94, and R93, as indicated on the printed circuit board of thecamera.) 2.2.3 Exemplary Modifications to the Software-Based Interfaceand Control of an Existing Digital Electronic Camera

It will be seen to be one of the strengths of the present invention thatno modification is needed to the firmware within the camera, nor thesoftware within a connecting computer. It will be understood, however,that such minor modifications as might be required are well within theskills of a practitioner of the digital computer programming arts.

For example, the Photoman Plus camera has a command set the detailnature of which is not of particular concern in the present application.

Using this instruction set software for control of the camera wasmodified in accordance with the space mission of the camera.

The Fotoman Plus camera software architecture is based on a boot codestored in the Fotoman Plus camera ROM. This main code stored in theFotoman Plus camera RAM is known as FOTOWARE. This code operates theFotoman Plus camera, performs the data compression, and manages thecommunications with an external computer through a serial link.

The Fotoman Plus camera software architecture is also based on anexploitation code, known as FOTOTOUCH, based on an external computer.This code contains a dialogue/acquisition segment, an executable namedFOTOMAN.EXE, and an image processing segment.

Finally, the Fotoman Plus camera software architecture is also based anative mode communication program TERM permitting ASCII commands—used incommanding the Fotoman Plus camera—to be entered via a keyboard.

The camera modification plan called for a special version of theFOTOWARE that permitted programmed (i) disabling of the flash, (ii)manual setting of the exposure time, and (iii) control of the batterycounter. The battery counter is a model of the battery maintained by theFOTOWARE, which does not measure any physical quantity from thebatteries. However, the battery counter must be above a certain level,before the Fotoman can take a picture.

However, if the camera batteries are removed and replaced, the onboardsoftware assumes that the replacement batteries are uncharged. As thepower circuitry for the digital camera replaces the batteries, on powerup, the counter will read zero and the camera will not be able to take apicture. By controlling the counter, the programmer(s) can change theerroneous indication of insufficient power, and can take a pictureimmediately. Flash control is recommended, as the flash will bephysically disabled.

FOTOTOUCH or any other standard image manipulation package can be usedin the ground station to view and process the images, which aredownloaded in standard JPEG format.

2.2.4 Exemplary Use of a Modified Existing Digital Electronic Camera

The present invention deals with a digital electronic camera modifiedfor underwater use. It is known to attempt to modify a digitalelectronic camera for a specific applications environment, to wit: thespace borne application of the Fotoman Plus camera.

In that application full new software supports cameradialogue/acquisition with the spacecraft CPU, and interfaces the cameralinto the main control module of the spacecraft. This software performsthe following tasks: 1. turning on and off the Fotoman Plus; 2.uploading FOTOWARE from the PROM into the Fotoman Plus RAM at a giventime; 3. sending orders to take pictures to the Fotoman; 4. Request andreceiving status, contact, and image inventory information; and 5.retrieving pictures from the Fotoman, to be stored in the CPU, whichwill be sent at a later time to the ground station.

These tasks can be performed using the 16 commands set of provided inthe Native Mode Toolkit.

Typical tasks for the modified FotoMan executable under software controlare to 1. take a picture at a given time (using the on-board clock); and2. download a picture #n stored in CPU memory.

For further explanation see the Fotoman Plus camera User's Guide (abasic user's guide) and the Fotoman Plus Camera Native Mode Toolkit(logical interface specifications) supplied by Logitech Inc., FremontCalif. 94555. See also JPEG documentation and source code at ftp site:<ftp.uu.net/graphics/jpeg file jpegsrc.v4.tar.Z>; and generalinformation on image compression from the list at FAQ of the Internetnewsgroup at <http://comp.compression.research>.

SUMMARY OF THE INVENTION

The present invention contemplates a weatherproof and watertight digitalcamera that is designed to operate both on land and underwater to greatdepths. The camera is preferably hermetically sealed, and is thusimpervious to contamination both from the atmosphere—such as may arisefrom wind-blown sand and smoke—and from water and like fluids, includingduring full immersion including at great depths and pressures.

The present invention particularly contemplates a camera which istotally encapsulated, preferably by being cast in plastic, with no sealsor penetrating pins, wires or other objects whatsoever. The underwatercamera so constructed is absolutely incapable of leaking: it has noholes nor any joints. Nonetheless to being hermetically sealed, thedigital camera can be retrieved from its encasement if required ordesired.

Furthermore, the present invention particularly contemplatesencapsulated digital cameras having no air spaces inside, which cantherefore be used at extreme depths.

Still furthermore, the present invention particularly contemplatesencapsulated digital cameras with adjustable optics that are immersed inwater when the digital camera is placed in water. The optics are thusadjustable without necessity of being placed in a watertight enclosure.

Finally, the present invention particularly contemplates new andimproved means of communicating each of (i) information, (ii) electricalpower and (iii) control across a watertight barrier particularly as mayencapsulate and protect a digital electronic camera.

1. A Waterproof Digital Electronic Camera System

The present invention contemplates a weatherproof and watertight digitalcamera that is designed to operate both on land and underwater to greatdepths. The camera is preferably hermetically sealed, and is thusimpervious to contamination both from the atmosphere—such as may arisefrom wind-blown sand and smoke—and from water and like fluids, includingduring full immersion including at great depths and pressures.

Nonetheless that the camera is hermetically sealed, its case, and allnecessary electrical and digital electrical communication with thecamera, are economically manufactured.

The economy of the case results primarily because there are absolutelyno passages though the case of the camera, nor are any waterprooffittings employed. Indeed, in one of its embodiments the case of thecamera is formed by completely encapsulating the camera, and some modestauxiliary electronics, within a solid block of, preferably, plasticduring a potting process.

The economy of communication is because the camera uses standardwireless communication links. Communication of image data from thecamera to the exterior of its transparent case is preferably via anoptical, and more preferably an infrared optical or RF link.

The watertight digital electronic camera so constructed is furthercharacterized in that communication of an actuation signal to theshutter of the camera is via a magnetic or mechanical-optical coupling.In one embodiment a trigger circuit based on a Hall-effect sensor or aReed relay, and located interior to the sealed case, produces anelectrical signal suitable to actuate the camera's existing shuttercircuit whenever a small permanent magnet exterior to the case isbrought into proximity, normally by manual movement in a simple slidingmechanism in a manner suggestive of a standard shutter release.

The watertight digital electronic camera so constructed is still furthercharacterized in that the camera has, quite conventionally, arechargeable source of power, normally a battery. This rechargeablepower source is, however, recharged quite unconventionally via aninductive coupling. In the preferred embodiment an oscillating,alternating current (a.c.), electromagnetic field external to the caseis inductively coupled into (i) an inductive coil internal to the case.Also internal to the case, (ii) a bridge rectifier rectifies thealternating current induced in the inductive coil to produce a directcurrent, and (iii) a regulating and charging circuit conditions thisdirect current into power to charge the rechargeable power source.

As a still further major aspect of the present invention, the case—whichis normally formed quite snug to the camera and its auxiliary electroniccircuits—may be filled with an optically-transparentelectrically-dielectric liquid. The case may even be formed by potting:solidifying a liquid polymer that extends into all regions and volumesof the case—including inside the camera—into a solid block ofoptically-transparent electrically-dielectric plastic. Thisconstruction, which leaves the enclosed volume of the case substantiallyentirely devoid of gas, permits that the waterproof camera may be usedat great depths of at least a mile, and may be non-destructivelysubjected to correspondingly great hydrostatic pressures. Any necessarypreset to the lens system of the camera to account for the differingindexes of refraction of air and of the potting plastic is contemplated.

2. An Underwater Digital Electronic Camera System

Therefore, in one of its aspects the present invention will berecognized to be embodied in a waterproof digital electronic camerasystem. The system includes (i) a digital electronic camera, and (ii) aconverter, within (iii) an enclosure.

The (i) digital electronic camera has a digital electrical signalinterface for downloading image information from the camera.

The (ii) converter converts signals upon the digital electrical signalinterface to optical or, preferably, RF signals.

The (iii) enclosure hermetically seals water and air tight both (i) thedigital electronic camera and (ii) the converter. The enclosure istransparent in at least an area of lens of the digital electronic cameraso that pictures may be taken through the enclosure, and so that anyoptical signal output of the converter so that optical signalscontaining image information are communicable exterior to the camera.Note that if an RF link is used to retrieve data from the camera, thenthe casing need not be optically transparent for this communication. Thecase will, however, be substantially transparent to radio frequencyenergy.

The (i) digital electronic camera typically has a serial digitalelectrical signal interface, and most commonly an RS-232 or USBinterface, thus making that (ii) the converter is converting signalsupon the serial digital electrical signal interface to serial opticalsignals. The preferred converter in particular includes (i) an RS-232 orUSB to TTL signal converter converting RS-232, USB, or other serialdigital electrical signals to Transistor-Transistor Logic (TTL) serialdigital electrical signals, (ii) an encoder-decoder converting the TTLelectrical signals to electrical signals that are suitably encoded so asto be converted to optical or radio signals for further transmission,and (iii) an electrical-to-optical signal converter converting theencoded electrical signals to optical or radio signals, and transmittingthe optical or radio signals through the enclosure.

Particularly in the case of an RF link, digital signals from the cameramay be converted to RF signals through a digital RF modem, a device wellfamiliar to practitioners of the art of communications engineering.

Further in the preferred system of the invention, the digital electroniccamera conventionally has a shutter circuit for activating the shutter,to which shutter circuit electrical connection may suitably be made.This shutter circuit is preferably connected to a trigger circuitexterior to the digital camera but within the enclosure. The shuttercircuit serves to take some stimulus external to the enclosure and toproduce responsively thereto an electrical signal which, when and assupplied to the shutter circuit, will activate the shutter of thedigital electronic camera.

The trigger circuit may be implemented in several different variants. AHall-effect sensor responsive to a magnetic field can be used to producea signal output, with an amplifier amplifying this signal output forapplication to the shutter circuit as the electrical signal responsivelyto which the shutter circuit will activate the shutter of the digitalelectronic camera. Triggering of the Hall-effect sensor may be realizedby the simple expedient of manually moving a permanent magnet, externalto the enclosure, into physical proximity to the Hall-effect sensor thatis within the enclosure.

Alternatively, the trigger circuit may be based on a Reed relay sensorwhich is also responsive to a magnetic field to produce the electricalsignal responsively to which the shutter circuit will activate theshutter of the digital electronic camera.

Still further, the trigger and other control circuits may be controlledvia a mechanical-optical coupling which also does not requirepenetration of the enclosure. An LED and a photo sensor device areplaced on each side of a hole in the enclosure that has optically clearmaterial to at least two opposed sides. When the camera operator'sfinger or other obstruction, such as the plunger of a switch, is placedin the hole of the enclosure and between its opposed sides, then anoptical link is interrupted which, after some simple circuitry, resultsin an electrical signal being sent to the camera to control the shutteror effect some other desired control.

Still further in the preferred system of the invention, the digitalelectronic camera has, as is conventional, a rechargeable power source,normally a battery, for providing power to at least (i) the digitalelectronic camera and also, in the case of the system of the invention,(ii) a signal converter which is external to the camera but still withinthe enclosure. The overall system preferably then further includes acharging circuit, exterior to the camera but within the enclosure, forconverting some stimulus external to the enclosure into power suitableto recharge the rechargeable power source. The stimulus is preferably anoscillating, alternating current (a.c.), electromagnetic field.Accordingly, the preferred charging circuit includes (i) an inductivecoil in which alternating current is induced by an oscillatory magneticfield external to the enclosure, (ii) a bridge rectifier rectifying thealternating current of the inductive coil to produce a direct current,and (iii) a regulating and charging circuit conditioning the directcurrent into power to charge the rechargeable power source.

The enclosure of the digital electronic camera and its associatedauxiliary electronics is structurally simple and inexpensive, butfunctionally sophisticated. In one preferred variant the camera and theconverter (and any other incorporated features such as the triggercircuit and/or the charging circuit) are entirely potted in an opticallyclear dielectric material. This optically clear dielectric pottingmaterial is preferably drawn from the group consisting essentially ofplastic and hydrocarbon liquids, such as polycarbonate plastic, and ismore preferably an epoxy resin or silicone encapsulant.

In a first variant of this potting, discussed further in section 3,below, the potting may extend into the interior volumes of the camera(and anything else, such as the inductive coil), so that, ultimately,the enclosure contains only solid masses, and is devoid of any gaswhatsoever. In another, second, variant the (potted, or otherwisesealed) enclosure contains both solid and liquid masses, only, and thereis still essentially no gas whatsoever within the enclosure nor withinthe camera that is within the enclosure. In this variant the liquid isan optically clear dielectric, and thus interferes with neither theoptical functions of the camera nor the electrical functions of thecamera and of the converter. In a final variant the potting covers theimage detector—such as a CCD—of the camera, but an adjustable lensassembly of the camera remains outside the potted enclosure. In thiscase the lens becomes surrounded with water when the camera is immersedin water.

3. An Encapsulated Waterproof Digital Electronic Camera System

Therefore, in another of its aspects the present invention will berecognized to be embodied in a waterproof digital electronic camerawhere the optics and electronics of the camera are permanently within asolid mass of optically clear dielectric material, and where the cameracontains essentially no gases whatsoever. By this construction thecamera may suitably be immersed to great depth within the ocean withoutcrushing.

In one variant of construction the digital electronic camera is pottedinside and out to be within a solid block of optically clear dielectricmaterial, preferably plastic and more preferably clear epoxy resin suchas Master Bond EP37-3LV.

In another variant of construction, all the camera electronics includingpower, switch controls, and electronic imager, are cast in clearplastic. However, the lenses which focus the image onto the imager areimmersed in, and focus through, the surrounding water.

In another variant of construction the digital electronic camera iswithin an optically clear liquid dielectric material, the camera and itsliquid being held within a liquid-tight exterior case that is itselfoptically clear in at least a region where an image is received throughthe case and into a lens of the camera. The preferred liquid is a liquidhydrocarbon, and is more preferably ethanol.

In another variant of construction the digital electronic camera iswithin a block of clear yet flexible potting material which can be cutwith a knife. Such a material would provide a hermetic seal and alsoallow the camera to be retrieved for repair or replacement. Thepreferred encapsulant is Master Bond Mastersil 151 (or similar silicone)encapsulant or Master Bond EP30DP or similar polymer encapsulant.

4. An Underwater Watch

As a further extension of the broad concepts of the present invention acompletely sealed underwater watch can be made by encasing a digitalwatch, including its electronics and battery, inside a clear plasticslab. The settings of the watch can be changed using the hall-effectmagnetic proximity switches described above. The watch battery can alsobe recharged as previously described for the waterproof digitalelectronic camera.

Alternatively, the watch can simply be fitted with a single batterywhich will last for several years; the life of the watch. (An optionalphotovoltaic array permits recharging.) The watch is economical yetoperable at great depths and pressures since it is entirely embedded inplastic and there are no air spaces inside.

These and other aspects and attributes of the present invention willbecome increasingly clear upon reference to the following drawings andaccompanying specification.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring particularly to the drawings for the purpose of illustrationonly and not to limit the scope of the invention in any way, theseillustrations follow:

FIG. 1 is a cross-sectional top plan view of a first, air-filled,preferred embodiment of a waterproof digital electronic camera systemaccording to the present invention.

FIG. 2 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIG. 1, particularly showing a preferred shutter actuation interface.

FIG. 3 is a combination electrical and mechanical schematic diagram of apreferred embodiment of a waterproof digital electronic camera systemaccording to the present invention, previously seen in FIGS. 1 and 2,particularly showing a preferred optical-link data interface.

FIG. 4 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 3, particularly showing a preferred power switchinterface.

FIG. 5 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 4, particularly showing a preferred recharginginterface.

FIG. 6 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 5, particularly showing a first variant of theconstruction of a transformer within the preferred recharging interfacepreviously seen in FIG. 5.

FIG. 7 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 5, particularly showing a second variant of theconstruction of the transformer of the preferred recharging interfacepreviously seen in FIG. 5.

FIG. 8 is a picture of an embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 5, that employs an RF data link to retrieve images fromthe camera.

FIG. 9 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 5, particularly showing a third variant of theconstruction of the transformer of the preferred recharging interfacepreviously seen in FIG. 5 where a ferrite or iron core is only requiredin the part of the charging circuit outside of the camera, thus reducingthe weight of the camera itself.

FIG. 10 is a cross-sectional top plan view of an additional embodimentof the camera which is wholly potted in clear plastic, and which haslenses which are external and focus through the water in which thecamera is operating.

FIG. 11 is a combination electrical and mechanical detail schematicdiagram of an optical switch that is an alternative to the magneticswitches previously shown for control of the camera.

FIG. 12 is a cross-sectional plan diagram of another embodiment of thisinvention in which components of a digital electronic camera areembedded in a block of dielectric potting material, the battery isembedded in a chamber of semi-rigid encapsulant, the lens is containedwithin a chamber of dry air, and connections for downloading andrecharging are made via a through the wall connector.

FIG. 13 is an enlarged diagram of the area labeled on FIG. 12 to betterillustrate use of normally open magnetic switches in the invention.

FIG. 14 is a cross-sectional plan diagram of yet another embodiment ofthis invention in which components of a digital electronic camera arecontained within a hermetically sealed chamber, and connections fordownloading and recharging are made via external contacts which matewith a cradle.

FIG. 15 is a sketch illustrating conversion of USB electrical signals(pictures) to optical signals for transmission to devices external tothe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although specific embodiments of the invention will now be describedwith reference to the drawings, it should be understood that suchembodiments are by way of example only and are merely illustrative ofbut a small number of the many possible specific embodiments to whichthe principles of the invention may be applied. Various changes andmodifications obvious to one skilled in the art to which the inventionpertains are deemed to be within the spirit, scope and contemplation ofthe invention as further defined in the appended claims.

The present invention is embodied in an underwater electronic digitalcamera which never needs to be opened except perhaps, optionally, forreplacement of a rechargeable battery. Even this apparent limitation to,and difficultly in, preserving the watertight integrity of the camerahas a solution which will be described below.

1. The Housing

A cross-sectional top plan view of a first, air-filled, preferredembodiment of a waterproof digital electronic camera system 1 accordingto the present invention is shown in FIG. 1. An entire digitalelectronic camera 11, including its optics 111, are contained within awaterproof case, or housing, 12. The housing 12 is preferablyconstructed of two plastic encasings 121 and 122, one fitting inside theother. The smaller inner encasing 121 is fitted over the camera 11 andits optics 111, forming a compartment 13. This compartment 13 is filledwith air in a first variant embodiment of the camera system 1 and itshousing 12, and with fluid or solid, polymerized, plastic in a secondvariant embodiment of the camera system 1 and its housing 12.

Control wires 14 and (2) power wires 151, 152 connect the camera 11through holes in the inner housing 121 respectively to (1) switches161-163 and infrared (IR) PC interface link 17, (2) a power switch 181,and (iii) a battery 184 (itself connected to recharging circuit 183 andcharging coil 182). Clear plastic resin is poured into the spaceinterior to the outer housing 122 but exterior to the inner housing 121.This forms an economical yet hermetic housing capable of withstandinghigh underwater pressures at depths in excess of 500 feet.

A mass-produced version may be fabricated as a single casting ofpolycarbonate, Lucite.sup.^(SM) plastic (Lucite is a trademark of Rohm &Haas, Inc.), or clear epoxy. The inner air compartment then consists ofa thin-walled clear plastic box 121 embedded in a solid potting, orcasting, which holds the optics 111 of the camera 11 aligned in the aircompartment until the plastic cures.

A variation of this embodiment consists of encasing the cameraelectronics in clear plastic, while the optics remain external andimmersed in liquid. This embodiment is shown in FIG. 10 and will bedescribed in a later section.

Another variation of this embodiment would consist of casting the camerain an encapsulant which is clear, yet is soft enough that it can be cutshould it be necessary to remove or service the camera. Master BondMastersil material 151 is ideal for this application, with bothexcellent optical clarity and tough yet flexible consistency. Thisembodiment also provides resistance to vibration and shock for thecamera components. Since the encapsulant is flexible, the outer housing12 should be hard to provide resistance to pressure. The encapsulantstill provides the optically-clear, hermetically-sealed, boundary.

2. The Switches

Switches 161-163, 181 in the form of Reed relay proximity switches orHall-effect devices are placed near the outer wall of the outer housing122. To the outside of the housing 122, small rubber beads 191-194, eachwith an associated magnet 201-204 mounted on its outer surface, areplaced near each proximity switch 161-163, 181. By depressing the rubberbeads 191-194 with the fingers the associated magnets 201-204 arebrought closer to the associated switch, activating the switches161-163, 181. As may later best be understood by reference to thepartial schematics of FIGS. 3-5, this magnetic switching mayalternatively be accomplished by Hall Effect semiconductor switches (atleast in the locations of switches 161-163)—which also results in a moresensitive switch design.

Hall-effect semiconductors also have the advantage of no moving partswithout any requirement for such gas space—required by the Reedrelays—as may hinder use of the camera at great depth and pressure.However, for the gating of main power (see the pictorial partialschematic of FIG. 4) a reed switch is superior since there will not beany leakage current. The main power switch 181 is unlike the otherswitches 161-163 in that a latching mechanism must be provided. A simplesliding element as is diagrammatically illustrated in FIG. 4, or,alternatively, a sideswipe lever (not shown), entirely fabricated fromplastic can work to selectively emplace a magnet, normally embeddedinside the manually slidable or otherwise movable part, into proximitywith, or separation from, the switch 181.

A preferred variant of any of the switches 161-163 (shown in FIG. 1) isshown in detail in the combination electrical and mechanical schematicblock diagram of FIG. 2.

The first variant preferred shutter actuation interface includes amagnet 201 mounted on slide switch 1611 having a sliding lever 1613 andretained in the illustrated position by elastic bands, or plasticsprings, 1612. Pressing with the fingers on the lever 1613 in thedirection of vector A moves the side switch into the stop 1614,positioning magnet 204 proximate to Hall effect sensor 1615 andproducing an electrical signal which, as amplified in amplifier 1616,suffices to trigger the shutter of the camera 11 (not shown in FIG. 2,shown in FIG. 1) electrically connected to wire 1617. The Hall effectsensor 1615 is preferably Micronics type HAL 1145VA. The amplifier 1616is preferably industry standard part number 7400.

The switch 181, which controls the application of power from the battery184 to the camera 11, will be more particularly discussed in followingsection 4.

3. The Data Interface

The data interface of the waterproof digital electronic camera system ofthe present invention, for example an infrared serial personal computerinterface including the infrared (IR) PC interface link 17 shown in FIG.1, is illustrated in the combined schematic and diagram of FIG. 3.

The preferred PC interface takes place through an infrared (IR) PCinterface link 17 consisting of an RS-232C to TTL converter 171, anencoder-decoder 172 and an infrared IrDa compliant transceiver 173. Itreceives serial data in the RS-232C interface format upon two 115,200bit per second (bps) signal lines 174 from the digital electronic camera11.

Then encoder-decoder 172 is preferably Hewlett-Packard type HSDL-7001.The infrared IrDa compliant transceiver is preferably Hewlett-Packardtype USDL-1001. Together these components transmit the data receivedfrom the digital electronic camera 11 upon a digital optical, and moreparticularly an IrDA-compliant infrared, link.

These infrared pulses are detected by an IrDA adapter 3 to a personalcomputer (PC) 4. The preferred IrDA adapter 3 is the “Jeteye IrDAadapter” available from Extended Systems, Inc. This component convertsthe received infrared pulses back into an electrical RS-232C, interfaceformat.

Accordingly, in the present invention electrical data signals from thedigital electronic camera 11 are translated into optical pulses in theIR spectrum and passed through the transparent wall of the camera'shousing 12 to an integrated IR detector and signal converter, or IrDaAdapter 3, on the other side. The IR interface can easily handle thebandwidth required for data transmission in accordance with the RS-232Cinterface standard, even at high baud rates. The entire process isopaque to both (i) the digital electronic camera 11 and the firmwareoperating therein, and to (ii) the PC 4 and the software operatingtherein.

In FIG. 8, an equivalent link is shown using a preferred radio frequency(RF) link for the purpose of communicating the image data to a PC orother device outside the camera. The signals from the camera—nominallyin accordance with the RS-232 or Universal Serial Bus (USB) interfacestandards—are input to an imbedded RF communications device (373) whichhas been designed to convert RS-232 (or, alternatively, USB) datastreams for transmission and reception over RF. The FreewaveTechnologies DGR24RFA is an example of an off-the shelf module thatcould be used for this purpose. However, many more digital RF modemdevices, such as those supporting the Bluetooth standard, could be usedat a variety of frequencies for this purpose.

The basic principal of the present invention that (i) signals from thecamera can be converted to modulated radio frequency (RF) signals, fedto an antenna 373 a and that (ii) these RF signals will traverse thecamera casting without the need for penetrating wires which are prone toleakage, is the same no matter what particular (i) camera, and (ii)wireless digital transmission standards, and protocols, are involved. Apractitioner of the wired and wireless digital communication arts willrecognize that the present invention may be realized with many different(i) wired and (ii) wireless communications standards, and that manysuitable standards are presently (circa 2000) implemented insemiconductor chips or chip sets, and are not difficult of use in theunderwater camera system of the present invention.

4. The Power Switch

The preferred power actuation interface shown in FIG. 4 again uses amagnet 204, now mounted on toggle switch 1811 having a swing arm 1812retained in the illustrated position by a latch 1813. Moving under forceof the fingers, the magnet 204 proximate to the Reed relay switch 181closes this Reed relay 1814, gating power through the path therebyestablished from the battery 184 to the camera 11 (both shown in FIG.1).

5. The Recharging Interface

A charging coil 182—preferably with a ferrite core (as will be moreparticularly illustrated in FIGS. 6, 7, and 9)—is located inside theplastic outer housing 122. This charging coil connects to a chargingcircuit 183 and through this circuit to a battery 184.

When the battery 184 is to be recharged, another coil carrying analternating current (not shown in FIG. 1, shown in FIGS. 6 and 7) isplaced outside the other housing 121 proximately to the charging coil182, and is aligned to induce current in this internal charging coil182. The outer coil acts as the primary winding of a transformer whilethe inner, charging, coil 182 acts as the secondary. The alternatingcurrent inductively induced in the inner (secondary) charging coil 182is then rectified, filtered and regulated in the charging circuit 182and applied as a d.c. current to charge the battery 184. In this way thebattery 184 can be charged without any need for opening the housing 122,or even for having any wires to penetrate the housing 122. The battery184 is charged and recharged entirely while it is continuously withinthe plastic housing 122.

A detail combination electrical and mechanical schematic block diagramof the preferred embodiment of the recharging circuitry for thewaterproof digital electronic camera system according to the presentinvention, previously seen in FIGS. 1 through 4, is shown in FIG. 5. Anexternal source of a.c. power 5 is inductively coupled throughtransformer 18, the secondary winding of which is the charging coil 182located inside the housing 12 (shown in FIG. 1). The a.c. currentinduced in the charging coil 182 (a transformer winding) is communicatedto rectifier 1831, normally a simple diode bridge, and filtered as ad.c. voltage in capacitor 1832. The d.c. voltage and current isconditioned in battery charging circuit 1833 and applied to chargebattery 184. Power from the battery 184 may optionally be regulated involtage regulator 1834 before application to camera 11 (shown in FIG.1).

These same components of FIG. 5, now in conjunction with a first, and asecond, variant embodiments of the transformer 18, are respectivelyillustrated in FIGS. 6 and 7. The physical design of the transformer 18a of FIG. 6 realizes good inductive coupling between the primary andsecondary coils of the transformer because the primary coil is (in termsof the flow of magnetic flux) located across the secondary coil. Thetransformer 18 configuration requires that the charger for thecamera—which is, of course, normally used only when the camera is not inuse for imaging—have a greater thickness than does the camera, whichsome users may find objectionable. Although the primary coil is still,in terms of the flow of magnetic flux, located across the secondary coilin the variant embodiment of FIG. 7, the primary and secondary windingsof the transformer 18 are of equal thickness, and the charger for thecamera 11 may be as thin as is the camera itself.

FIG. 9 is a combination electrical and mechanical detail schematicdiagram of the preferred embodiment of a waterproof digital electroniccamera system according to the present invention, previously seen inFIGS. 1 through 5, particularly showing a third variant of theconstruction of the transformer of the preferred recharging interfacepreviously seen in FIG. 5 where a ferrite or iron core is only requiredin the part of the charging circuit outside of the camera, thus reducingthe weight of the camera itself. This configuration also offers a moreefficient transfer of energy since the primary and secondary windingsare concentrically wound around the same core when the core is insertedinto the indentation as shown in FIG. 9.

In this most preferred embodiment of FIG. 9 the primary and secondary ofthe transformer are both wound around the same core.

A single piece of ferrite or other ferrous core material is located onthe primary and inserted into a hole in the camera during charging. Thusthe ferrite or iron core is only required in the part of the chargingcircuit outside of the camera, beneficially reducing the weight of thecamera itself. Compared to the other configurations shown, thisembodiment offers more efficient transfer of energy from the primarylocated outside the camera to the secondary windings inside the cameracasting.

6. A Solidly Encapsulated Embodiment

An alternative second embodiment of the hermetically sealed digitalelectronic camera in accordance with the present invention isessentially the same as the first embodiment with one importantdifference: the entire camera including both the camera electronic andoptics are cast into clear casting resin or other clear plastic.

The optics may be constrained to be immovable, and thus focus free.These focus free optics may be preset, or, in extreme cases, customdesigned by aid of standard ray-tracing lens design programs that accordconsideration to the indices of refraction of all media in the opticalpath, so as to correctly accommodate the index of refraction of theclear plastic medium which is, of course, different than that of air.However, the optics may alternatively be moveable (such as to focus),and located outside the encapsulated enclosure of the camera, asexplained in section 6.3 below.

The solidly encapsulated design offers the advantage of easy manufacturewhile permitting camera operation to virtually any depth under waterbecause, with no airspace within the camera, there is no pressuredifferential between the outside and the inside of the camera. Like themore rudimentary hermetic sealing of the camera with some gas stillinside, the second embodiment is enabled by the fact that the cameranever needs to be opened during all phases of operation.

6.1 A Fluid-Filled Housing Variation on the Second Embodiment

A variation on the second embodiment of the invention employs a housingthat is fluid-filled, or that is at least in part fluid filled. Thepreferred fluids are clear dielectrics. Both common mineral oil andsynthetic gel suffice. However, if the fluid is present in the opticalpath, fluids with high optical clarity are preferred. These fluids areassociated with fluid-filled optical light pipes, and may readily belocated in, inter alia, the patent literature on this precise subject.

Note that certain fluids transmit better in certain regions of theoptical spectrum. Clearly any fluid in the optical path of the digitalcamera should be chosen in consideration of the frequency of the imagesdesired to be registered by the camera. For example, the electronicsensor array plane of the camera need not be a Charge Coupled Device(CCD) targeted on visible light, but may instead be an active pixelarray sensitive, in the manner of the common use of these arrays intelescopes, to infrared light. Clearly if the digital electronic camerais to capture images in infrared light, any liquid (or solid) in theoptical path would be highly transparent to light of this frequency.

The housing is closed around the fluid or gel, and experiences zeropressure differential. Yet the camera electronics are protected. Thisvariant embodiment has the advantage that housing could be opened andthe camera electronics removed for servicing. Also, in the event thatthe camera optics must move, such as to focus, the fluid or gel canaccommodate this.

6.2 A Semi-Rigid Encapsulant Variation on the Second Embodiment

Another variation to the second embodiment consists of casting thecamera, including optics, in an encapsulant which is clear, yet is softand flexible enough so that it can be cut should it be necessary toremove or service the camera. Master Bond Mastersil 151 is ideal forthis application, with both excellent optical clarity and tough yetflexible consistency.

This variant embodiment also provides resistance to vibration and shockfor the camera components. Since the encapsulant is flexible, it shouldbe provided with some outer hard shell to provide durability. In thiscase, however, the optics could not be adjusted so they must be capableof focus-free operation. The optics would need to be redesigned toaccount for the index of refraction of the encapsulant.

6.3 A Solidly Encapsulated Variant Embodiment Having Optics External tothe Enclosure, and Immersed when the Encapsulated Camera is in Water

A third embodiment is shown in FIG. 10. In this third variant embodimentthe electronic digital camera electronics 1002, including the electronicimager device 1003, are cast in hard plastic 1001 with no air spaces—asin the second embodiment. But here the optics 1004 1005 are locatedoutside the casting, being immersed in the external water environment.

This embodiment offers the advantage of zero pressure differential inthe camera's optics, yet these optics can move to allow focus and zoomby mechanical movement in a cylinder 1006 in a manner functionallyidentical to the lens mounting and movement of a land (air) camera.

In this third variant embodiment the optics need to be designed to focusthrough water rather than air. This is readily accomplished with moderncomputerized optical design programs, which accord for assigning anindex of refraction to all media in which light travels.

The third variant embodiment is substantially incapable of leakage atany depth while supporting both focusing and zooming. The zero-pressuredifferential allows fabrication to be small since the encapsulant andhousing do not have to withstand deformation due to water pressure.

7. An Underwater Camera with a Variant Mechanical-Optical Switch

An variant optical switch design, usable on the underwater camera systemof the present invention, is shown in FIG. 11. Like the magnetic design,there are no penetrations of the clear, cast, enclosure of the camera.

However, the difference is that an optical coupling is used rather thanmagnets. The plunger 1104 is depressed (or alternatively the operator'sfinger is inserted in the hole) which then interrupts the light beamnormally existing between the LED 1101 and the photo sensor 1102. Theoutput current of the photo sensor 1102 then drops. This current drop istranslated into the desired control signal by simple electronicsfamiliar to engineers versed in the art of digital electronic design.

This variant embodiment of the camera system has the advantage that nomagnets are needed and accidental placement in an external magneticfield will not inadvertently activate the controls. The LED and photosensor pair may operate in the visible light or, preferably, in theinfrared portion of the spectrum to reduce potential interference.

8. Optional Replacement of the Rechargeable Battery

Any replacement of the rechargeable battery 184 which may at some pointbecome necessary may, in accordance with the present invention,optionally be made possible by having a battery compartment located nearthe outside of the housing. The battery 184 is installed in a suitablebattery holder and then this sub-compartment is filled with, preferably,a semi-rigid plastic encapsulant (Master Bond EP30DP) which provides ahermetic seal around the battery 184 and all wires and contacts and hasgood adhesion properties. When the battery 184 is to be replaced, thesemi-rigid encapsulant is cut away with a small knife and the battery184 replaced. Upon replacement of the battery 184, the batterycompartment is then refilled with the same encapsulant.

9. Gas-Filled, and Solid- or Liquid-Filled, Embodiments of theUnderwater Electronic Digital Camera

In one embodiment of an underwater camera in accordance with the presentinvention, the optics of the camera, or the entire camera, isencapsulated within an air compartment within the camera housing. Thisdesign has the advantage that the camera optics do not need to beredesigned for atmospherically-based usage, but the disadvantage is thatthere will be a pressure differential between the outside water pressureand lower gas (air) pressure inside the compartment, which will, at somedepth, become a limiting factor in the design. However, even this designis operable at depths exceeding five hundred feet (500′) with the use ofonly inexpensive plastic materials because the housing is made from asingle piece of cast plastic with no openings or seals. There is thus noproblem with leakage which exists with conventional O-ring seal designsfor underwater cameras.

In another embodiment of an underwater camera in accordance with thepresent invention, the entire camera is embedded in an optically clearplastic potting material (such as polycarbonate), including, mostnotably, the (focus-free) optics of the camera. When the camera isdelivered into use this potting plastic is solid, and permanent. In avariant of this embodiment the camera, and more normally the camera andthe entire interior of the watertight case within which it and anyaccompanying auxiliary electronics are housed, is filled with a clearliquid, normally ethanol.

This embodiment, and both these variants, have the disadvantage that thecamera optics have to be designed for the different index of refractionof the clear plastic potting material, or the liquid, as opposed to air.Also, if the potting plastic solidifies hard (which is normal), thenthere cannot be any moving parts, making that the camera optics have tobe focus-free, and unmoving. When the camera enclosure is filled with aclear, dielectric, fluid, mechanical focusing of the camera optics isstill permitted. However, care has to be taken that (1) the immersionfluid is not normally a satisfactory lubricant, (2) material from thecamera may become dissolved and/or dispersed in the fluid, clouding itsclarity and interfering with photography, and/or (3), depending upon thedifferential compressibility of the immersion fluid versus water, thefluid may still slightly compress and the camera body distort at verygreat depths, normally a mile or more. The advantage of the secondembodiment is that an inexpensively housed and adapted conventionaldigital electronic camera can be made to be operable at essentially anydepth. This is because a total absence of air inside the camera housingprecludes that any pressure differential should arise between theoutside and the inside of the camera. The fact that this can be achievedwith an inexpensive design makes this embodiment of an underwater camerain accordance with the present invention particularly novel andattractive.

The third embodiment, shown in FIG. 10 consists of the electronics andimager chip being totally encapsulated, with the optics being locatedexternal to the casting and focusing through water. This embodiment hasthe advantage of zero pressure differential yet optics that can move toallow focus and zoom.

FIG. 12 is a cross-sectional plan diagram of another embodiment of thisinvention. Much of the interconnect wiring and some components are notshown for clarity of comprehension. In addition, external activatingcontrols are also not illustrated. The external controls are constructedin accordance with the previous descriptions.

In this embodiment, digital camera is understood to mean the componentswithout the case. The major components that will be discussed are thelens 2001, the charge coupled device 2004, a rechargeable power sourceor battery 2008, an electronic storage device 2012 for storing picturestaken by the digital electronic camera in digital electronic form,control electronics 2016, a signal interface 2020 for downloading thepictures from the electronic storage device and the flash unit. 2024.

All components 2001, 2004, 2008, 2012, 2016, 2020 and 2024 are enclosedin a block of gas-free dielectric potting material 2030 so that the lens2001 is positioned normal to one wall of the block. Methods for moldingsuch gas-free blocks of potting material containing components are wellknown. In this way the components are hermetically sealed water and airtight and the entire invention can be immersed to great depth within theocean without crushing.

The dielectric potting material 2030 can be any convenient plastic butthe preferred materials are cured epoxy resin, cured silicone resin andcured polyurethane resin. The potting material 2030 can be any color butit must be transparent in the area 2034 of the lens 2001 and the area2038 of the flash 2024 so that pictures may be taken through theenclosure 2030.

This embodiment, similarly to other embodiments, must be able tocommunicate with devices eternal to the invention for recharging thepower source 2008 and downloading the pictures from the storage device2012 via the signal interface 2020. Preferably, in this embodiment,communication is via a through the wall 2040 connector 2042. See FIG.13. Preferably, the connector is a male connector with fairly widespacing between the pins 2046 so that salt water does not become trappedinside the connector 2042. To prevent corrosion of the pins 2046 by saltwater, they should be gold plated. To prevent shorting between pins 2046in salt water a normally open magnetic switch 2050 is included in oneconnection 2054 to the battery 2008 and in one connection 2058 to thesignal interface 2020. The mating female connector contains a magnet2062 so that the magnetic switches 2050 close and connections can bemade for recharging and downloading.

Alternatively picture signals may be transmitted exterior to theinvention optically. Preferably the picture signals output by the signalinterface conform to the United Serial Bus (USB) protocol. A schematicof devices which convert USB signals to optical signals is illustratedin FIG. 15.

In order to obviate the necessity of redesigning the lens 2001 foroperation within dielectric potting material 2030 the lens 2001 can becontained within a chamber 2066 so that potting material 2030 is keptaway from the lens 2001 during molding of the enclosure. In order toprevent fogging of the lens 2001 this chamber should be filled with dryair 2068.

In order to allow replacement of the battery 2008 it may be separatelycontained within another chamber 2070. This chamber must go through andbe flush with the exterior wall 2040 of the enclosure. In this way, thebattery can be embedded within a semi-rigid encapsulant 2074 by wellknown techniques. The outer surface of this semi-rigid encapsulant 2074becomes flush with the exterior wall 2040 of the enclosure. Later on,the semi-rigid encapsulant 2074 may be removed, the battery 2001replaced, and the cavity 2070 resealed with semi-rigid encapsulant 2074by well known techniques.

FIG. 14 is a cross-sectional plan diagram of yet another embodiment ofthis invention Much of the interconnect wiring and some components arenot shown for clarity of comprehension. In addition, external activatingcontrols are also not illustrated. The external controls are constructedin accordance with the previous descriptions.

In this embodiment, digital camera is understood to mean the componentswithout the case. The major components that will be discussed are thelens 2001, the charge coupled device 2004, a rechargeable power sourceor battery 2008, an electronic storage device 2012 for storing picturestaken by the digital electronic camera in digital electronic form,control electronics 2016, a signal interface 2020 for downloading thepictures from the electronic storage device and the flash unit. 2024.

All components 2001, 2004, 2008, 2012, 2016, 2020 and 2024 are enclosedin hermetically sealed enclosure 2090 so that the lens 2001 ispositioned normal to one wall 2040 of the enclosure 2090. The enclosureis preferably made from a box 2094 having an open side 2096 with a lid2098 fastened on to this open side 2096. The box 2094 and lid 2098 arepreferably made from thick plastic. The box 2094 is preferably injectionmolded so that it has no seams. The lid 2098 is preferably attached tothe box 2094 by ultrasonic welding. The components are supported withinthe enclosure 2090 by appropriate support blocks 2118 attached to theinterior of the enclosure 2090. In this way the components arehermetically sealed water and air tight and the entire invention can beimmersed to great depth within the ocean without crushing. In order toprevent fogging of the lens 2001 enclosure 2090 should be filled withdry air 2068.

The plastic that the enclosure 2090 is made of can be any color but itmust be transparent in the area 2102 of the lens 2001 and the area 2106of the flash 2024 so that pictures may be taken through the enclosure2090.

This embodiment, similarly to other embodiments, must be able tocommunicate with devices eternal to the invention for recharging thepower source 2008 and downloading the pictures from the storage device2012 via the signal interface 2020. Preferably, in this embodiment,communication is via a through the wall 2040 connector 2042. See FIG.12. Alternatively, connection is made via a set of contacts a set ofcontacts 2106 on the exterior 2040 of the enclosure 2090. To preventcorrosion of the contact 2106 by salt water, they should be gold plated.To prevent shorting between contacts 2106 in salt water, a normally openmagnetic switch 2050 is included in one connection 2054 to the battery2008 and in one connection 2058 to the signal interface 2020. The matingcradle 2110 contains mating contacts 2114 and a magnet 2062 so that themagnetic switches 2050 close and connections can be made for rechargingand downloading.

Alternatively picture signals may be transmitted exterior to theinvention optically. Preferably the picture signals output by the signalinterface conform to the United Serial Bus (USB) protocol. A schematicof devices which convert USB signals to optical signals is illustratedin FIG. 15.

In order to allow replacement of the battery 2008 it may be separatelycontained within another chamber 2070. See FIG. 12.

In another alternative, charge in the battery 2008 may be monitored by amonitor device 2160 which then controls the charging current.

FIG. 15 is a sketch illustrating conversion of USB electrical signals(pictures) to optical signals for transmission to devices external tothe invention. Typically a USB device outputs 4 signals 2202 on 4channels 2200 and receives 4 signals 2206 on the same channels 2200. Theoutput signals 2202 from the signal interface 2020 go to an electricalto optical converter 2204 a which converts the output signals 2202 tofour optical signals 2208. These are transmitted across the wall 2040 toanother electrical to optical converter 2204 b. In this converter 2204 bthe optical signals 2208 are converted to output electrical signals 2202again for transmission over 4 channels to the PC.

In the other direction input signals 2206 from the PC are converted inthe converter 2204 b to 4 input optical signals 2212, transmitted acrossthe wall to the other converter 2204 a, where they are converted to 4input signals 2206 again for transmission to the signal interface 2202.

10. Recapitulation, and Extension, of the Concepts of the PresentInvention

There are at least four primary features to the waterproof digitalelectronic camera system of the present invention. First, the method ofdesigning the housing within the housing accords for an air space whichcontains the camera or at least the camera optics. Second, the design ofthe electronic switches permits operator control of the camera while itis submerged nonetheless that this these switches require no holesthrough the housing whatsoever, thus preserving the water-tightintegrity of the housing. Third, the method of recharging the battery ofthe camera does not require opening of the housing, nor the presence ofany holes or penetrating pins or wires in the housing. Fourth, theinfrared or radio interface to a communicating PC requires neither anyopening of the casing, nor any openings in the casing.

These concepts of the present invention described herein thisspecification are of broad applicability. Namely, the concepts of (i)potting the auxiliary electronics and the digital electronic cameratogether to provide an inexpensive watertight housing, (ii) magneticallyactivating essential switches of the both the momentary and dual-statetypes, (iii) communicating data to a computer upon an infrared or radiodata interface through a clear housing, (iv) breaking or otherwisedisrupting a frangible or removable seal to optionally replace abattery, (v) filling the housing with a dielectric fluid which mayeither remain liquid or solidify, and (vi) still other concepts, can allbe applied to diverse underwater devices other than digital electroniccameras.

For example, an underwater light could be made using these designfeatures. Also, an all-digital video camera, which are now available,can be housed the same way, and the pictures retrieved to a computerinterface, in the identical manner as the digital electronic stillcamera of the present invention.

Accordingly, the concepts of the present invention should be understoodto be broadly applicable to digital electronic equipments deployed inunderwater, marine, adverse weather and contaminated environments ofvarious natures.

By way of a further particular example, and underwater digital watch cangreatly benefit by several of the concepts of the present invention. Thewatch may employ each and any of the (i) encapsulating housing, (ii)inductively coupled battery recharging, and/or (ii) magneticallyactuated switching concepts of the present invention. The may be, inparticular, completely potted and sealed in strong plastic forunderwater operation.

In accordance with the preceding explanation, variations and adaptationsof the hermetically sealed digital electronic camera system inaccordance with the present invention will suggest themselves to apractitioner of the electronics and optics packaging arts. For example,data could be communicated to and from the camera over and inductiveelectrical link in the manner of U.S. Pat. No. 5,455,466. A design neednot embrace each and every disparate aspect of the present invention tobe within the scope of the invention, as defined by the attached claims.At least when the battery is not replaced, the underwater camera of thepresent invention is the first, to the inventor's knowledge, to house afunction camera in a case that is totally without such holes, ororifices, as have commonly previously fitted mechanisms for transmittingmechanical forces, or wires for communicating electrical power and/orsignals. Even if the battery replacement option is employed, thehermetically sealed digital electronic camera system of the presentinvention can fairly be described as “seal-less” in that its case, whilecertainly “sealed”, has no “seals” in the sense that some crack ororifice through which water and/or contamination might otherwise enterhas to be “patched over” with a “seal” that otherwise permits themovement of something—mechanical force or electricity orwhatever—through the region of the seal.

In summary, the lack of air inside the camera of the present inventionpermits leak proof operation at considerable depths which, hitherto,only much more costly cameras could provide. Additionally, the lack ofneed for any seals provides a guarantee against leakage at moderatedepths which even the most costly underwater cameras do not currentlyprovide.

In accordance with these and other possible variations and adaptationsof the present invention, the scope of the invention should bedetermined in accordance with the following claims, only, and not solelyin accordance with that embodiment within which the invention has beentaught.

1. A waterproof digital electronic camera system comprising: a) adigital electronic camera having a lens, a charge coupled device, arechargeable power source, an electronic storage for storing picturestaken by said digital electronic camera in digital electronic form,control electronics, and a signal interface for downloading saidpictures from said electronic storage device; b) an enclosure means forhermetically sealing water and air tight and supporting said digitalelectronic camera within said enclosure means so that said lens ispositioned normal to one wall of said enclosure means; said enclosurebeing transparent in at least an area of said lens so that pictures maybe taken through said enclosure; said enclosure means designed to beimmersed to great depth within the ocean without crushing; c) means forrecharging said power source from a charger external to said enclosure;and d) means for downloading pictures from said electronic storagedevice via said signal interface to a remote storage device external tosaid enclosure.
 2. A waterproof digital electronic camera systemcomprising: a) a digital electronic camera including a lens, an imagesensor, a rechargeable power source, an electronic storage device forstoring pictures taken by said digital electronic camera in digitalelectronic form, control electronics, and a signal interface fordownloading said pictures from said electronic storage device; b) ahousing configured to hermetically seal therein said digital electroniccamera water and air tight and to support therein said digitalelectronic camera so that said lens is fixed relative to at least onewall of said housing that comprises at least a first transparent areaalong an optical path defined by said lens and image sensor so thatpictures may be taken through said first transparent area of said atleast one wall of said housing, and wherein said housing being securelycloseable; c) wherein said rechargeable power source comprises a primarycoil around a conducting core and is configured to gather charge from anexternal charger that comprises a secondary coil that is disposedoutside of said housing when closed and hermetically sealed, whereinsaid secondary coil is configured to couple inductively with saidprimary coil to recharge the power source; and d) wherein said signalinterface is configured for downloading said pictures from saidelectronic storage device via said signal interface to a remote storagedevice disposed outside of said housing when closed and hermeticallysealed.
 3. A waterproof digital electronic camera system according toclaim 2, wherein said conducting core comprises ferrite or iron.
 4. Awaterproof digital electronic camera system according to claim 2,wherein said signal interface is configured to convert signals tooptical signals for optical transmission through a second transparentarea of said housing.
 5. A waterproof digital electronic camera systemaccording to claim 2, further comprising a remote control configured toactivate said control electronics from outside of said housing whenclosed and hermetically sealed.
 6. A waterproof digital electroniccamera system according to claim 5, wherein said remote controlcomprises a magnetic switch.
 7. A waterproof digital electronic camerasystem according to claim 2, wherein said housing is configured tosecurely close around one or both of a fluid or gel.
 8. A waterproofdigital electronic camera system according to claim 2, wherein saidrechargeable power source comprises: a) a rectifier electrically coupledto the primary coil; b) a charging circuit electrically connected to therectifier and said rechargeable power source; and c) a voltage regulatorconnected to said rechargeable power source to provide power to thedigital electronic camera.
 9. A waterproof digital electronic camerasystem according to claim 2, wherein further comprising: a) a connectorcoupled to said signal interface; and b) a magnetic switch.
 10. Awaterproof digital electronic camera system according to claim 2,wherein said secondary coil is disposed within a recess defined at anouter surface of said housing.
 11. A waterproof digital electroniccamera system according to claim 2, wherein said rechargeable powersource comprises: a) a capacitor connected in parallel with saidrechargeable power source; b) a charging circuit electrically connectedto said capacitor and said rechargeable power source; and c) a voltageregulator connected to said rechargeable power source to provide powerto the camera system.
 12. A waterproof digital electronic camera systemaccording to claim 11, further comprising a set of mating contacts, saidset of mating contacts including a magnet configured to couple with saidset of contacts.
 13. A waterproof digital electronic camera systemaccording to claim 2, wherein said signal interface comprises: a) a setof contacts accessible at an outer surface of a wall of said housing; b)a set of electrical connections connecting said set of electricalcontacts with said signal interface; and c) a magnetic switch.
 14. Awaterproof digital electronic camera system according to claim 13,further comprising a set of mating contacts comprising a magnetconfigured to couple with said set of contacts.
 15. A waterproof digitalelectronic camera system according to claim 2, wherein said housingcomprises a gas-free dielectric potting material molded to a selectedshape.
 16. A waterproof digital electronic camera system according toclaim 15, wherein said dielectric potting material comprises one or moreof silicone resin, epoxy resin, or polyurethane resin.
 17. A waterproofdigital electronic camera system according to claim 15, wherein saidhousing comprises a chamber filled with dry air that contains said lens.18. A waterproof digital electronic camera system according to claim 2,wherein said rechargeable power source is located within a cavityseamlessly sealed to the exterior of said housing within a semi-rigidremovable encapsulant that is configured to permit replacement andresealing of said rechargeable power source.
 19. A waterproof digitalelectronic camera system according to claim 2, wherein said housingcomprises an integral box having an open side, and a lid configured tocouple to and enclose said housing to provide said hermetic seal.
 20. Amethod of fabricating a waterproof digital electronic camera systemcomprising: a) obtaining a digital electronic camera having a lens, animage sensor, an electronic storage device for storing pictures taken bysaid digital electronic camera in digital electronic form, and controlelectronics, and a signal interface for downloading said pictures fromsaid electronic storage device; b) forming a housing configured tohermetically seal therein said digital electronic camera water and airtight and to support therein said digital electronic camera so that saidlens is fixed relative to at least one wall of said housing thatcomprises at least a first transparent area along an optical pathdefined by said lens and image sensor so that pictures may be takenthrough said first transparent area of said at least one wall of saidhousing, and wherein said housing being securely closeable; c) couplinga rechargeable power source to said digital electronic camera thatcomprises a primary coil around a conducting core and is configured togather charge from an external charger that comprises a secondary coilthat is disposed outside of said housing when closed and hermeticallysealed, wherein said secondary coil is configured to couple inductivelywith said primary coil to recharge the power source; and d) coupling asignal interface to said digital electronic camera that is configuredfor downloading said pictures from said electronic storage device viasaid signal interface to a remote storage device disposed outside ofsaid housing when closed and hermetically sealed.